Is rectal bleeding normal for dog after enema?

My vet gave my dog a enema yesterday to clear her bowels for an xray. When we got home last night she had a watery red discharge from her rectum, it has continued all night, and now she keeps running outside trying to go to the bathroom but only a little fecies comes out with blood. I called my vet and they said it is normal. I am worried, she is drinking water.